Gas cylinders are used to store and charge high-pressure gas, such as liquefied petroleum gas (LPG), compressed natural gas (CNG), bio gas, oxygen, or hydrogen. In particular, these gas cylinders need to have sufficient strength so that high-pressure gas can be stored and kept in the gas cylinder for a long time.
A gas cylinder according to the related art is manufactured by producing a resin liner using a liner blower machine and curing the resin liner and then by reinforcing strength by wrapping fiber reinforced plastics (FRP) or fiber around an outer circumference of the resin liner.
However, it is difficult to obtain sufficient strength at which the liner can withstand various high-pressure gases, only by reinforcing the thickness of the liner by manually wrapping FRP or a fiber material around an outer circumferential surface of the liner at room temperature. Even when the number of reinforcement layers disposed on the outer circumferential surface of the liner is increased, the thickness and the volume of the gas cylinder increase.
Also, a method for manufacturing gas cylinders according to the related art has a considerable defect rate and lowered productivity caused by the defect rate, and efforts for improving a manufacturing process have been continuously made so as to solve the problems.
(Patent document 1) KR10-1999-0085513 A1
(Patent document 2) KR10-2007-0099688 A1
(Patent document 3) KR10-0746248 B1
(Patent document 4) KR10-2010-0090732 A1